Gain limits of a Thick GEM in high-purity Ne, Ar and Xe

TL;DR

This study investigates how gas purity affects the avalanche gain in Thick GEM detectors using noble gases, revealing that purification reduces gain but N2 admixtures can enhance it, impacting detector performance in rare event detection.

Contribution

It demonstrates the influence of gas purity and N2 admixtures on gain in THGEMs, providing insights for optimizing noble gas detectors in cryogenic applications.

Findings

Gain drops with gas purification using non-evaporable getters.

N2 admixtures enable higher achievable gains.

Implications for two-phase cryogenic detector operation.

Abstract

The dependence of the avalanche charge gain in Thick Gas Electron Multipliers (THGEM) on the purity of Ne, Ar and Xe filling gases was investigated. The gain, measured with alpha-particles in standard conditions (atmospheric pressure, room temperature), was found to considerably drop in gases purified by non-evaporable getters. On the other hand, small N2 admixtures to noble gases resulted in high reachable gains. The results are of general relevance in the operation of gas-avalanche detectors in noble gases, particularly that of two-phase cryogenic detectors for rare events.